Liverpool's first dock was the world's first enclosed commercial dock, the Old Dock, built in 1715. The Lyver Pool, a tidal inlet in the narrows of the estuary, which is now largely under the Liverpool One shopping centre, was converted into the enclosed dock. Further docks were added and eventually all were interconnected by lock gates, extending 7.5 miles (12.1 km) along the Liverpool bank of the River Mersey. From 1830 onwards, most of the building stone was granite from Kirkmabreck near Creetown, Scotland.

The interconnected dock system was the most advanced port system in the world. The docks enabled ship movements within the dock system 24 hours a day, isolated from the high River Mersey tides. Parts of the system are now a World Heritage Site.